An embodiment of the present invention relates to a nonvolatile memory device and a method of operating the same.
In recent years, there has been an increasing demand for nonvolatile memory devices which can be electrically programmed and erased and which do not require the refresh function of rewriting data at specific time intervals.
The nonvolatile memory cell of the nonvolatile memory device can be electrically programmed and erased. The program and erase operations are performed using the threshold voltage of the cell which varies when electrons are moved by a strong electric field applied to the thin oxide layer of the cell.
The nonvolatile memory device includes a memory cell array in which memory cells for storing data are arranged in a matrix form and page buffers each for writing data into specific memory cells of the memory cell array or for reading data stored in specific memory cells. The page buffer includes a pair of bit lines coupled to specific memory cells, a register configured to temporarily store data to be written into a specific memory cell or to temporarily store data read from a specific memory cell, a sense node configured to sense the voltage level of a specific bit line or a specific register, and a bit line selection unit configured to control whether or not to couple the specific bit line to the sensing node.
In conventional program and verification operations of such a nonvolatile memory device, the program operation is sequentially performed on even pages and odd pages, and the verification operation is also performed. Thus, the effect of coupling noise between the bit lines of the even and odd pages on the sense operation can be minimized/reduced. However, with a reduction in the size of a cell, it becomes difficult to reduce such coupling noise between the bit lines using this method. Accordingly, there is a need for a sense method capable of minimizing/reducing coupling noise between the bit lines.